drm/i915: Downgrade unknown firmware warnings

If we have released no firmware yet for a platform, stop scaring the
consumer and merely note its expected absence.
Signed-off-by: Chris Wilson <chris@chris-wilson.co.uk>
Cc: Petri Latvala <petri.latvala@intel.com>
Reviewed-by: Joonas Lahtinen <joonas.lahtinen@linux.intel.com>
Link: https://patchwork.freedesktop.org/patch/msgid/20181009111259.20807-1-chris@chris-wilson.co.uk

drivers/gpu/drm/i915/intel_guc_fw.c

@@ -78,7 +78,8 @@ static void guc_fw_select(struct intel_uc_fw *guc_fw)
 		guc_fw->major_ver_wanted = KBL_FW_MAJOR;
 		guc_fw->minor_ver_wanted = KBL_FW_MINOR;
 	} else {
-		DRM_WARN("%s: No firmware known for this platform!\n",
+		dev_info(dev_priv->drm.dev,
+			 "%s: No firmware known for this platform!\n",
 			 intel_uc_fw_type_repr(guc_fw->type));
 	}
 }